Limited bandwidth in portions of the electro-magnetic spectrum remains a challenge in wireless communications. In general, data transfer rates of approximately 3 to 5 bits-per-second-per-Hertz (bits/second/Hertz) can be achieved using conventional modulation schemes with high-order alphabets of approximately several bits-per-symbol. These modulation schemes often require sophisticated modems to correctly detect data in the presence of noise and other interference sources. Many newer modulation schemes such as quadrature amplitude modulation (QAM) combine amplitude and phase modulation, often using inefficient linear power amplifiers to prevent signal distortion. In addition, available spectral bandwidth is in many cases limited and highly regulated. For applications using beyond line-of-sight communications such as satellite links, bandwidth allocations may be particularly limited and valuable.